The subject matter disclosed herein relates generally to maintenance of intelligent electronic devices used in rugged environments and, more particularly, to systems and methods for facilitating predictive maintenance of intelligent electronic devices based on continuous monitoring of operating conditions, exposure to external factors, and reliability models embedded within the devices.
Electrical grids including incorporated generation, transmission, distribution, and energy conversion means are often operated with the aid of intelligent electronic devices (IEDs). Such devices protect against faults and other abnormal conditions, monitor and meter energy usage, and control other aspects of electrical grid operations. Intelligent electronic devices include, but are not limited to including, protective relays, remote terminal units, programmable logic controllers (PLCs), meters, local human machine interfaces (HMIs), Ethernet switches and/or routers, modems, and other similar devices.
Intelligent electronic devices are often installed and operated in harsh environments, such as high voltage substation control houses, medium voltage switchgear, power plants, industrial plants, and motor control centers. As such, IEDs are exposed to conditions such as extreme temperatures, electromagnetic interference, electrical surges, mechanical shocks and vibration, and chemical agents. At least some known IEDs are designed to withstand such conditions as prescribed by industry standards, established design practices, and/or based on competition between manufacturers.
At least some known IEDs perform critical functions within an electrical grid, such as protection functions and/or control functions. As such, IEDs are needed that remain fully functional during a commissioned time. To ensure that the IEDs retain their desired functions and perform when and as necessary, the IEDs are periodically checked and/or maintained. Periodic maintenance procedures have changed since the use of a previous generation of protection, control, and/or metering devices that included electro-mechanical and analog technologies. At least some known periodic maintenance procedures include visually inspecting an IED for signs of problems and periodically taking the IED out of service, isolating the IED from the rest of the system to which it belongs, and testing the functionality of the IED. The maintenance intervals of such periodic maintenance procedures may be between 2 and 5 years, and are based on factors such as past experience of a given user, a make of the IED being inspected, average operating conditions, a criticality of the application, and other related factors.
Such periodic maintenance procedures, however, are not optimized to consider IEDs having different life expectancies and/or failure rates. IEDs may be installed in operating conditions that differ considerably when compared to average expected operating conditions. Variable operating conditions include easily verifiable factors such as average ambient temperature, and hidden factors such exposure to electromagnetic interference and local operating temperature. Often, all IEDs in a given facility are maintained, regardless of the make and/or operating conditions of the IEDs. As a result, some percentage of IEDs are “over maintained” and some are “under maintained,” causing unexpected failures to occur.
Such periodic maintenance procedures miss a significant potential for cost savings to users and/or operators of IEDs. For example, maintenance is an expensive operation due to the amount of associated labor and, in cases where device redundancy has not been employed, the maintenance may require shutting down protected and/or controlled processes and/or assets. In addition, unexpected failures of IEDs require emergency-style responses that involve unscheduled work, unscheduled spare material usage, additional urgency and a need to work without proper preparation, and/or unscheduled shutdowns of protected and/or controlled assets, which may then trigger shutdowns of associated process steps.
At least some known IEDs include microprocessors that enable the IEDs to collect and analyze information from the sensors. However, systems and/or methods are needed that employ information collection and analysis to understand the operating conditions and exposures of IEDs in combination with an embedded knowledge of the life expectancies of the IEDs, such as a reliability model, to generate predictive maintenance requests and/or signals.